The pectins were isolated from sterile stems of E. arvense (EA, yield 5.9%) and E. sylvaticum (ES, yield 4.8%) (Equisetaceae) using ammonium oxalate extraction after preliminary treatment with dilute HCl (рH 4.0). The pectins possessed high molecular weight (Mw, 340-360 kDa), high GalA content (ca. 85%), low degrees of methyl-esterification (14-16%) and acetylation (3-8%). NMR analysis indicated extensive regions of partially methyl-etherified and 3-O-acetylated HG and minor regions of low branched RG in the fragment isolated after hydrolysis of pectin EA by pectinase. Pectin EA produced a higher viscosity solution, formed a stronger and more rigid ionotropic hydrogel than pectin ES. The pectins scavenged DPPH and hydroxyl radicals, but not the superoxide radical and hydrogen peroxide. Phenolic compounds (0.11 and 0.23%) associated with polysaccharide moieties were apparently responsible for the differences in the anti-DPPH scavenging activity of pectins EA and ES (63 and 49%). The findings suggested that pectin from E. arvense should be more perspective than pectin from E. sylvaticum on their use as components of wound healing remedies.
Keywords: 3,5-Xylenol (PubChem CID: 7948); Calcium chloride (PubChem CID: 5284359); Characterization; Ethanol (PubChem CID: 702); Horsetails; Hydrochloric acid (PubChem CID: 313); Hydrogen peroxide (PubChem CID: 784); NMR; Pectin; Radical scavenging activity; Sodium chloride (PubChem CID: 5234); Textural property; Trolox (PubChem CID: 40634); Xanthine (PubChem CID: 1188); d-galacturonic acid (PubChem CID: 439215).
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